I did cloth at night with wool for my daughter. Now that I have two in diapers it's just easier to use sposies at night, plus, I don't think there's anything that'll hold my son. He's 5 months and 18lbs. Last night I had him in a size 4 Huggies night time diaper with a wool cover and he leaked, a lot. Is there anything else to try? I think the size 5 will be way to big for him. He's also pooping a bit at night so he's getting a rash. Should I just get up and change him at night?

I would put a little barrier cream on him if you know he's pooping, and also change that diaper (if you're awake and aware of it). There were times my son slept in a poopy diaper, unbeknownst to me (being asleep LOL) and he would be so red in the morning!